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Friday, July 8, 2016

Carbon Capture and Storage: No Stone Unturned

Technologies for carbon capture and storage often don't garner much political support. Those who think rising levels of carbon in the atmosphere aren't much of a problem see little purpose for investments in technology to capture that carbon. Many of those who do think rising carbon emissions are a problem are emotionally wedded to a particular solution--reducing use of fossil fuels and growth of solar and wind power, combined with better batteries--and they sometimes view carbon capture and storage as an excuse to continue the use of fossil fuels. My own belief is that the risks of climate change (and other environmental costs of fossil fuel use) aren't likely to have one silver-bullet answer, and that all options are worth research and exploration, including not just non-carbon and low-carbon energy sources, but also energy conservation efforts and geoengineering, along with carbon capture and storage.

Back in 2005, the Intergovernmental Panel on Climate Change published one of its doorstop tomes called Carbon Dioxide Capture and Storage, summarizing what what known at the time. Here's a sense of the tone of the report, emphasizing both the potential of carbon capture and storage (CCS) and the uncertainties about realizing that potential (footnotes deleted for readability):

In most scenarios for stabilization of atmospheric
greenhouse gas concentrations between 450 and 750 ppmv CO2 and in a least-cost portfolio of mitigation options,
the economic potential of CCS would amount to 220–
2,200 GtCO2 (60–600 GtC) cumulatively, which would
mean that CCS contributes 15–55% to the cumulative
mitigation effort worldwide until 2100, averaged over a
range of baseline scenarios. It is likely that the technical
potential for geological storage is sufficient to cover the
high end of the economic potential range, but for specific
regions, this may not be true.
Uncertainties in these economic potential estimates are
significant. For CCS to achieve such an economic potential,
several hundreds to thousands of CO2 capture systems would
need to be installed over the coming century, each capturing
some 1–5 MtCO2 per year. The actual implementation of
CCS, as for other mitigation options, is likely to be lower than
the economic potential due to factors such as environmental
impacts, risks of leakage and the lack of a clear legal
framework or public acceptance ...

How has CCS evolved since then? The underlying idea here is to consider installing carbon capture technology at industrial or other facilities which use a lot of fossil fuels and where carbon emissions are especially high. The technology doesn't eliminate such industrial emissions, but holds some promise for reducing them substantially. The more recent estimates for potential of CCS seem to be at the very low end of what the IPCC discussed back in 2005. For example, the International Energy Agency produced a 2015 report called Carbon Capture and Storage:The solution for deep emissions reductions. When the title refers to "the solution," it dramatically oversells the actual content of the report. The conclusions are much more measured, focusing on CCS as a contributor to reducing carbon emissions in specific industrial settings that lack cost-effective alternatives to fossil fuels:

According to International Energy Agency (IEA) modelling, CCS could deliver 13% of the cumulative
emissions reductions needed by 2050 to limit the global increase in temperature to 2°C (IEA 2DS). This
represents the capture and storage of around 6 billion tonnes (Bt) of CO2 emissions per year in 2050, nearly
triple India’s energy sector emissions today.
Half of this captured CO2 in the 2DS would come from
industrial sectors, where there are currently limited or
no alternatives for achieving deep emission reductions.
While there are alternatives to CCS in power generation,
delaying or abandoning CCS in the sector would increase
the investment required by 40% or more in the 2DS, and
may place untenable and unrealistic demands on other low
emission technology options.

The Global CCS Institute keeps track of the projects that are actually underway and offers a summary in its report The Global Status of CCS 2015. The report counts seven large-scale CCS projects (that is, not counting pilot or research-level projects) operating globally in 2010, 15 operating in 2016, and 22 expected to be operating by 2020. For example, one of the large-scale projects in 2015 is the Quest project being operated by Shell Oil in Canada. As the report notes: "Launched in Alberta, Canada in November 2015,
the Quest project is capable of capturing
approximately 1 Mtpa of CO2
from the manufacture
of hydrogen for upgrading bitumen into synthetic
crude oil.
Quest is the first large-scale CCS project in North
America to store CO2
exclusively in a deep saline
formation, and the first to do so globally since the
Snøhvit CO2
Storage Project became operational in
Norway in 2008.
A case study prepared by Shell documenting
key learnings from the development of Quest
is available here." Saudi Arabia also started operating a large-scale CCS project, the first one in the Middle East region, in mid-2015.

Although the biggest effect of CCS technology in the near-term is likely to be focused on these kinds of industrial applications, there's also an intriguing possibility that it can do more through what has become known as BECCS--that is, Bio-Energy and Carbon Capture and Storage. Imagine an energy-generating facility with CCS technology that burns biomass--that is, fuel developed from waste materials produced by forestry, agriculture, and perhaps other sources. Biomass is a renewable resource: in effect, it captures carbon from the atmosphere. If that carbon is captured and stored, and then more biomass is created, and the carbon from that biomass is captured and stored in turn, and so on--the result is a source of energy with negative overall carbon emissions. For discussion, here's a boosterish 2012 report called Biomass with CO2 Capture and Storage (Bio-CCS): The Way Forward for Europe, produced on behalf of the European Biofuels Technology Platform and the Zero Emissions Platform. The IPCC has viewed this possibility as worth mentioning, too: for example, its 5th Assessment report in 2014 has comments like: "“Many models could not limit likely warming to below 2°C if bioenergy, CCS and their combination (BECCS) are limited.”

The large-scale CCS projects now underway will tell us a lot about the costs and effectiveness of the technology in reducing carbon emissions in the next few years. If the feedback seems favorable, then bio-energy with CCS is a likely next step.